1. Field of the Invention
The present invention relates to a current compensating device, especially to a current compensating device for an IC operating in high-voltage, the current compensating device provides a compensating current to the IC when the IC is operated in high-voltage and modulates PWM frequency at the same time.
2. Description of Prior Art
Power supply is an essential unit of electrical device and usually has a power converter. Among them, switch power supply uses pulse width modulation technology to modulate input power fed to load. PWM controller (or called pulse width modulator) turns on/off switches between power supply and load and changes a DC input voltage into a series of pulse voltage, then the pulse voltage is converted by transformer and diode to form smoothly DC voltage. The output voltage is compared with a reference voltage and voltage difference feedback to the PWM controller. If the output voltage is above desired voltage, the PWM controller reduces pulse width of input voltage so as to decrease supplying power and then the output voltage reply to desire voltage. Such that the power factor of the power supply is reduced when operating in high-voltage and then increase power loss.